U.S. patent application number 13/868472 was filed with the patent office on 2013-10-31 for vibrating reed, gyro sensor, electronic apparatus, and mobile unit.
This patent application is currently assigned to Seiko Epson Corporation. The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Keiji NAKAGAWA, Ryuta NISHIZAWA.
Application Number | 20130283910 13/868472 |
Document ID | / |
Family ID | 49461573 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130283910 |
Kind Code |
A1 |
NISHIZAWA; Ryuta ; et
al. |
October 31, 2013 |
VIBRATING REED, GYRO SENSOR, ELECTRONIC APPARATUS, AND MOBILE
UNIT
Abstract
A vibrating reed includes a base part. A drive vibrating arm, a
detection vibrating arm, and an adjustment vibrating arm extend
from the base part. A first adjustment electrode and a second
adjustment electrode are connected to the adjustment vibrating arm.
The first adjustment electrode generates an electrical signal in
first phase. The second adjustment electrode generates an
electrical signal in second phase opposite to the first phase. The
electrical signals of the adjustment electrodes are superimposed on
the detection signal of the detection vibrating arm, and thereby,
vibration leakage components are cancelled out. The adjustment
vibrating arm is partially sandwiched between a first electrode
piece and a second electrode piece, and the adjustment vibrating
arm is partially sandwiched between a third electrode piece and a
fourth electrode piece.
Inventors: |
NISHIZAWA; Ryuta;
(Matsumoto, JP) ; NAKAGAWA; Keiji; (Minowa,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
Seiko Epson Corporation
Tokyo
JP
|
Family ID: |
49461573 |
Appl. No.: |
13/868472 |
Filed: |
April 23, 2013 |
Current U.S.
Class: |
73/504.12 ;
310/365; 310/366 |
Current CPC
Class: |
G01C 19/5607 20130101;
G01C 19/5621 20130101; H01L 41/0475 20130101; G01C 19/56
20130101 |
Class at
Publication: |
73/504.12 ;
310/365; 310/366 |
International
Class: |
H01L 41/047 20060101
H01L041/047; G01C 19/56 20060101 G01C019/56 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 27, 2012 |
JP |
2012-102896 |
Claims
1. A vibrating reed comprising: a base part; a drive vibrating arm
and a detection vibrating arm extending from the base part; an
adjustment vibrating arm extending from the base part; a first
adjustment electrode provided above the adjustment vibrating arm
and generating an electrical signal in first phase; a second
adjustment electrode provided above the adjustment vibrating arm
and generating an electrical signal in second phase opposite to the
first phase, wherein the adjustment vibrating arm includes a first
surface, a second surface opposite to the first surface, a first
side surface and a second side surface connecting the first surface
and the second surface, a first groove formed on the first surface
and extending in a longitudinal direction of the adjustment
vibrating arm, and having a first wall surface at the first side
surface side and a second wall surface at the second side surface
side, and a second groove formed on the second surface and
extending in the longitudinal direction of the adjustment vibrating
arm, and having a third wall surface at the first side surface side
and a fourth wall surface at the second side surface side, the
first adjustment electrode includes a first electrode piece
provided above the first side surface, and second electrode pieces
provided above the first wall surface and the third wall surface,
and the second adjustment electrode includes a third electrode
piece provided above the second side surface, and fourth electrode
pieces provided above the second wall surface and the fourth wall
surface.
2. A vibrating reed comprising: a base part; a drive vibrating arm
and a detection vibrating arm extending from the base part; an
adjustment vibrating arm extending from the base part; first
adjustment electrodes being in contact with a piezoelectric member
provided above the adjustment vibrating arm in locations apart from
each other and generating electrical signals in first phase, and
second adjustment electrodes being in contact with the
piezoelectric member provided above the adjustment vibrating arm in
locations apart from each other and generating electrical signals
in second phase opposite to the first phase.
3. The vibrating reed according to claim 1, wherein the electrical
signal of the adjustment vibrating arm is in anti-phase with an
electrical signal of vibration leakage of the detection vibrating
arm.
4. The vibrating reed according to claim 2, wherein the electrical
signal of the adjustment vibrating arm is in anti-phase with an
electrical signal of vibration leakage of the detection vibrating
arm.
5. The vibrating reed according to claim 1, wherein a detection
electrode that generates an electrical signal in response to a
physical quantity applied to the drive vibrating arm is provided
above the detection vibrating arm, the first adjustment electrode
and the detection electrode are electrically connected, and the
second adjustment electrode and the detection electrode are
electrically connected.
6. The vibrating reed according to claim 2, wherein a detection
electrode that generates an electrical signal in response to a
physical quantity applied to the drive vibrating arm is provided on
the detection vibrating arm, the first adjustment electrode and the
detection electrode are electrically connected, and the second
adjustment electrode and the detection electrode are electrically
connected.
7. A gyro sensor comprising the vibrating reed according to claim
1.
8. A gyro sensor comprising the vibrating reed according to claim
2.
9. An electronic apparatus comprising the vibrating reed according
to claim 1.
10. An electronic apparatus comprising the vibrating reed according
to claim 2.
11. A mobile unit comprising the vibrating reed according to claim
1.
12. A mobile unit comprising the vibrating reed according to claim
2.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to a vibrating reed, a gyro
sensor using the vibrating reed, and an electronic apparatus, a
mobile unit, etc. in which the vibrating reed is incorporated.
[0003] 2. Related Art
[0004] For example, as described in Patent Document 1
(JP-A-5-256723), vibrating reeds used for gyro sensors are commonly
known. When angular velocity motion is applied to a drive vibrating
arm, the vibration direction of the drive vibrating arm changes due
to action of Coriolis force. A new force component is generated in
a specific direction in response to the Coriolis force. The force
component causes motion of a detection vibrating arm. Accordingly,
an output signal in response to the force component is output from
the detection vibrating arm. In the example described in Patent
Document 1, the detection vibrating arm and the drive vibrating arm
continuously form one vibrating arm.
[0005] The main body of the vibrating reed may be cut out from a
raw material such as a piezoelectric material, for example. For
cutting out, masks are placed on the front surface and the rear
surface of the raw material. When misalignment occurs between the
masks, the side surface of the drive vibrating arm is not
orthogonal to the front surface and the rear surface, but tilted.
When a processing error is caused in the sectional shape of the
drive vibrating arm on this account, the drive vibrating arm can
not vibrate within a specified hypothetical plane, but vibrates in
a hypothetical plane tilted from the specified hypothetical plane.
The so-called diagonal vibration is generated. The phenomenon is
called vibration leakage, and the vibration leakage component is
superimposed on the force component in the output signal of the
detection vibrating arm. As a result, the S/N-ratio of the output
signal is deteriorated. An angular velocity signal is output from
the vibrating reed with no angular velocity motion input thereto.
In Patent Document 2 (JP-A-2008-209215), a cut is formed in the
vibrating arm for removing the vibration leakage component. The cut
in the vibrating arm triggers reduction in mechanical strength of
the vibrating reed. In addition, as the vibrating reed becomes
smaller, the influence on the behavior of the vibrating reed by the
shape accuracy of the cut increases and further improvement of
processing accuracy is required. However, the improvement of
processing accuracy is difficult.
SUMMARY
[0006] An advantage of some aspects of the invention is to provide
a vibrating reed that may improve an S/N-ratio of an output signal
while maintaining mechanical strength.
[0007] (1) An aspect of the invention relates to a vibrating reed
including a base part, a drive vibrating arm and a detection
vibrating arm extending from the base part, an adjustment vibrating
arm extending from the base part, a first adjustment electrode
provided on the adjustment vibrating arm and generating an
electrical signal in first phase, a second adjustment electrode
provided on the adjustment vibrating arm and generating an
electrical signal in second phase opposite to the first phase,
wherein the adjustment vibrating arm includes a first surface, a
second surface opposite to the first surface, a first side surface
and a second side surface connecting the first surface and the
second surface, a first groove formed on the first surface and
extending in a longitudinal direction of the adjustment vibrating
arm, and having a first wall surface at the first side surface side
and a second wall surface at the second side surface side, and a
second groove formed on the second surface and extending in the
longitudinal direction of the adjustment vibrating arm, and having
a third wall surface at the first side surface side and a fourth
wall surface at the second side surface side, the first adjustment
electrode includes a first electrode piece provided on the first
side surface, and second electrode pieces provided on the first
wall surface and the third wall surface, and the second adjustment
electrode includes a third electrode piece provided on the second
side surface, and fourth electrode pieces provided on the second
wall surface and the fourth wall surface.
[0008] This vibrating reed may be used for detection of an angular
velocity. For detection of the angular velocity, vibration is
excited in the drive vibrating arm. In this regard, when angular
velocity motion is applied to the drive vibrating arm, the
vibration direction of the drive vibrating arm changes due to
action of Coriolis force. A new force component is generated in a
specific direction in response to the Coriolis force. The force
component causes motion of the detection vibrating arm.
Accordingly, an output signal in response to the force component is
output from the detection vibrating arm.
[0009] The force component causes motion of the adjustment
vibrating arm at the same time. The electrical signals are
respectively output from the first adjustment electrode and the
second adjustment electrode in response to the motion. The
inventors have found out that the component of vibration leakage
contained in the output signal of the detection vibrating arm may
be at least partially cancelled out by the electrical signals of
the first adjustment electrode and the second adjustment electrode.
When the electrical signals of the first adjustment electrode and
the second adjustment electrode are superimposed on the output
signal of the detection vibrating arm, the S/N-ratio of the output
signal is improved. In addition, the electrical signal of the first
adjustment electrode and the electrical signal of the second
adjustment electrode are in anti-phase with each other, and the
magnitudes of the electrical signals may be adjusted according to
the relative relation between the first adjustment electrode and
the second adjustment electrode. Therefore, whether the phase of
vibration leakage is in in-phase or anti-phase with the output
signal of the detection vibrating arm, the component of the
vibration leakage may be cancelled out. When the electrical signal
of the first adjustment electrode and the electrical signal of the
second adjustment electrode are balanced, the influence on the
output signal of the detection vibrating arm by the electrical
signals may be eliminated. In addition, for adjustment of the
electrical signals, it is only necessary that the shape of the
first adjustment electrode or the second adjustment electrode is
controlled, and the formation of cuts in the drive vibrating arm,
the detection vibrating arm, and the adjustment vibrating arm may
be avoided. The reduction in mechanical strength may be avoided.
The cuts are not formed, and the improvement in processing accuracy
is not necessarily required.
[0010] Specifically, in the vibrating reed, the adjustment
vibrating arm is partially sandwiched between the first electrode
piece and the second electrode pieces, and the adjustment vibrating
arm is partially sandwiched between the third electrode piece and
the fourth electrode pieces. As a result, the larger output signals
are obtained in the first adjustment electrode and the second
adjustment electrode. The adjustment range of vibration leakage may
be wider. The yield may be improved.
[0011] (2) Another aspect of the invention relates to a vibrating
reed including a base part, a drive vibrating arm and a detection
vibrating arm extending from the base part, an adjustment vibrating
arm extending from the base part, first adjustment electrodes being
in contact with a piezoelectric member provided on the adjustment
vibrating arm in locations apart from each other and generating
electrical signals in first phase, and second adjustment electrodes
being in contact with the piezoelectric member provided on the
adjustment vibrating arm in locations apart from each other and
generating electrical signals in second phase opposite to the first
phase.
[0012] This vibrating reed may be used for detection of an angular
velocity. For detection of the angular velocity, vibration is
excited in the drive vibrating arm. In this regard, when angular
velocity motion is applied to the drive vibrating arm, the
vibration direction of the drive vibrating arm changes due to
action of Coriolis force. A new force component is generated in a
specific direction in response to the Coriolis force. The force
component causes motion of the detection vibrating arm.
Accordingly, an output signal in response to the force component is
output from the detection vibrating arm.
[0013] The force component causes motion of the adjustment
vibrating arm at the same time. The electrical signals are
respectively output from the first adjustment electrode and the
second adjustment electrode in response to the motion. The
inventors have found out that the component of vibration leakage
contained in the output signal of the detection vibrating arm may
be at least partially cancelled out by the electrical signals of
the first adjustment electrode and the second adjustment electrode.
When the electrical signals of the first adjustment electrode and
the second adjustment electrode are superimposed on the output
signal of the detection vibrating arm, the S/N-ratio of the output
signal is improved. In addition, the electrical signal of the first
adjustment electrode and the electrical signal of the second
adjustment electrode are in anti-phase with each other, and the
magnitudes of the electrical signals may be adjusted according to
the relative relation between the first adjustment electrode and
the second adjustment electrode. Therefore, whether the phase of
vibration leakage is in in-phase or anti-phase with the output
signal of the detection vibrating arm, the component of the
vibration leakage may be cancelled out. When the electrical signal
of the first adjustment electrode and the electrical signal of the
second adjustment electrode are balanced, the influence on the
output signal of the detection vibrating arm by the electrical
signals may be eliminated. In addition, for adjustment of the
electrical signals, it is only necessary that the shape of the
first adjustment electrode or the second adjustment electrode is
controlled, and the formation of cuts in the drive vibrating arm,
the detection vibrating arm, and the adjustment vibrating arm may
be avoided. The reduction in mechanical strength may be avoided.
The cuts are not formed, and the improvement in processing accuracy
is not necessarily required.
[0014] (3) The electrical signal of the adjustment vibrating arm
may be in anti-phase with an electrical signal of vibration leakage
of the detection vibrating arm. The electrical signal of the
adjustment vibrating arm may cancel out the electrical signal of
the vibration leakage. Accordingly, the S/N-ratio of the output
signal may be improved.
[0015] (4) A detection electrode that generates an electrical
signal in response to a physical quantity applied to the drive
vibrating arm may be provided on the detection vibrating arm, the
first adjustment electrode and the detection electrode may be
electrically connected, and the second adjustment electrode and the
detection electrode may be electrically connected. The electrical
signal of the adjustment vibrating arm may be superimposed on the
output signal of the detection vibrating arm. The magnitude of the
electrical signal is adjusted. As a result of adjustment, the
electrical signal of the adjustment vibrating arm may cancel out
the component of vibration leakage. Accordingly, the S/N-ratio of
the output signal may be improved.
[0016] (5) The vibrating reed may be incorporated and used in a
gyro sensor. The gyro sensor may have the vibrating reed.
[0017] (6) The vibrating reed may be incorporated and used in an
electronic apparatus. The electronic apparatus may have the
vibrating reed.
[0018] (7) The vibrating reed may be incorporated and used in a
mobile unit. The mobile unit may have the vibrating reed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention will be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0020] FIG. 1 is a vertical sectional view schematically showing a
configuration of a gyro sensor according to a first embodiment.
[0021] FIG. 2 is an enlarged plan view schematically showing a
structure of a vibrating reed.
[0022] FIG. 3 is an enlarged partial plan view schematically
showing a configuration of a front surface of a second vibrating
arm.
[0023] FIG. 4 is an enlarged perspective plan view schematically
showing a configuration of a rear surface of the second vibrating
arm from the front side.
[0024] FIG. 5 is an enlarged partial plan view schematically
showing a configuration of front surfaces of a first vibrating arm
and a third vibrating arm.
[0025] FIG. 6 is an enlarged perspective partial plan view
schematically showing a configuration of rear surfaces of the first
vibrating arm and the third vibrating arm from the front side.
[0026] FIG. 7 is a perspective view of the vibrating reed
schematically showing vibration of the second vibrating arm, i.e.,
a drive vibrating arm.
[0027] FIG. 8 is a perspective view of the vibrating reed
schematically showing vibration of the first vibrating arm, i.e., a
detection vibrating arm.
[0028] FIG. 9A is a graph schematically showing a relationship
among vibration leakage, a detection signal of the first vibrating
arm, and a detection signal of the third vibrating arm, FIG. 9B is
an enlarged vertical sectional view of the first vibrating arm, and
FIG. 9C is an enlarged vertical sectional view of the third
vibrating arm.
[0029] FIG. 10A is a graph schematically showing a relationship
among vibration leakage, the detection signal of the first
vibrating arm, and the detection signal of the third vibrating arm,
FIG. 10B is an enlarged vertical sectional view of the first
vibrating arm, and FIG. 10C is an enlarged vertical sectional view
of the third vibrating arm.
[0030] FIG. 11A is a graph schematically showing a relationship
between detection signals of the third vibrating arm cancelled out
each other, and FIG. 11B is an enlarged vertical sectional view of
the third vibrating arm.
[0031] FIG. 12 is an enlarged vertical sectional view schematically
showing a structure of a third vibrating arm used for a gyro sensor
according to a second embodiment.
[0032] FIGS. 13A and 13B are enlarged vertical sectional views
schematically showing a structure of a first vibrating arm used for
a gyro sensor according to a third embodiment.
[0033] FIG. 14 is an enlarged partial plan view schematically
showing a configuration of a front surface of a vibrating reed in
the gyro sensor according to the third embodiment.
[0034] FIG. 15 is an enlarged perspective partial plan view
schematically showing a configuration of a rear surface of the
vibrating reed from the front side in the gyro sensor according to
the third embodiment.
[0035] FIG. 16 is an enlarged vertical sectional view schematically
showing a structure of a third vibrating arm used for a gyro sensor
according to a fourth embodiment.
[0036] FIG. 17 is an enlarged partial plan view schematically
showing a configuration of a front surface of a vibrating reed in
the gyro sensor according to the fourth embodiment.
[0037] FIG. 18 is an enlarged perspective partial plan view
schematically showing a configuration of a rear surface of the
vibrating reed from the front side in the gyro sensor according to
the fourth embodiment.
[0038] FIG. 19A is a graph schematically showing a relationship
among vibration leakage, a detection signal of the first vibrating
arm, and a detection signal of the third vibrating arm, FIG. 19B is
an enlarged vertical sectional view of the first vibrating arm, and
FIG. 19C is an enlarged vertical sectional view of the third
vibrating arm.
[0039] FIG. 20A is a graph schematically showing a relationship
among vibration leakage, the detection signal of the first
vibrating arm, and the detection signal of the third vibrating arm,
FIG. 20B is an enlarged vertical sectional view of the first
vibrating arm, and FIG. 20C is an enlarged vertical sectional view
of the third vibrating arm.
[0040] FIG. 21 is an enlarged vertical sectional view schematically
showing a structure of a third vibrating arm used for a gyro sensor
according to a fifth embodiment.
[0041] FIG. 22 is an enlarged vertical sectional view schematically
showing a structure of a third vibrating arm used for a gyro sensor
according to a sixth embodiment.
[0042] FIG. 23 is a plan view schematically showing a structure of
a vibrating reed used for a gyro sensor according to a seventh
embodiment.
[0043] FIG. 24 is a conceptual diagram schematically showing a
configuration of a smartphone as a specific example of an
electronic apparatus.
[0044] FIG. 25 is a conceptual diagram schematically showing a
configuration of a digital still camera as another specific example
of an electronic apparatus.
[0045] FIG. 26 is a conceptual diagram schematically showing a
configuration of an automobile as a specific example of mobile
unit.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0046] As below, one embodiment of the invention will be explained
with reference to the accompanying drawings. Note that the
embodiment to be explained does not unduly limit the intention
described in the appended claims is, and not all of the
configurations explained in the embodiment are not necessarily
essential as solving means in the invention.
(1) Configuration of Gyro Sensor according to First Embodiment
[0047] FIG. 1 schematically shows a configuration of a gyro sensor
11 according to the first embodiment. The gyro sensor 11 includes a
box-shaped container 12, for example. The container 12 includes a
container main body 13 and a lid member 14. The opening of the
container main body 13 is air-tightly covered by the lid member 14.
The internal space of the container 12 may be sealed in vacuum, for
example. The container 12 functions as a rigid body. At least the
lid member 14 may be formed from a conductor. When the lid member
14 is grounded, the lid member 14 may exert a shield effect for
electromagnetic wave.
[0048] A vibrating reed 15 and an IC (integrated circuit) chip 16
are housed in the container 12. The vibrating reed 15 and the IC
chip 16 are provided within the internal space of the container 12.
The vibrating reed 15 includes a main body 17 and a conducting film
18. The conducting film 18 is stacked on the surfaces of the main
body 17. The conducting film 18 may be formed using a conducting
material such as gold (Au), copper (Cu), or other metals. The
conducting film 18 may be formed by a thin film or a thick film. As
clearly seen from FIG. 1, the main body 17 of the vibrating reed 15
has a front surface 17a and a rear surface 17b. The front surface
17a spreads within a first reference plane RP1. The rear surface
17b spreads within a second reference plane RP2. The second
reference plane RP2 spreads in parallel to the first reference
plane RP1. Here, the entire main body 17 is formed by one
piezoelectric member. For the piezoelectric member, for example,
quartz may be used.
[0049] The vibrating reed 15 is cantilevered by the container main
body 13. For cantilever, a fixing part 19 is partitioned at one end
of the main body 17. A group of connecting terminals 21 are
provided in the fixing part 19. The group of connecting terminals
21 are formed by a part of the conducting film 18 spreading on the
rear surface 17b. The group of connecting terminals 21 include a
plurality of connecting terminals, i.e., pads made of a conducting
material. The details of the connecting terminals will be described
later. On the other hand, a group of conducting terminals 22 are
provided on the bottom plate of the container main body 13. The
group of conducting terminals 22 include a plurality of connecting
terminals, i.e., pads made of a conducting material. The group of
connecting terminals 21 of the vibrating reed 15 are bonded to the
group of conducting terminals 22 on the bottom plate. For bonding,
a conducting bonding material 23 such as solder bump or gold bump,
for example, may be used. In this manner, the vibrating reed 15 is
fixed to the bottom plate of the container main body 13 in the
fixing part 19. The group of conducting terminals 22 are connected
to the IC chip 16 via wires (not shown) of the conducting film 18.
The IC chip 16 may be bonded to the bottom plate of the container
main body 13, for example.
[0050] As shown in FIG. 2, the main body 17 of the vibrating reed
15 has a base part 25, a pair of first vibrating arms 26a, 26b, a
pair of second vibrating arms 27a, 27b, and a pair of third
vibrating arms 28a, 28b. The front surface 17a and the rear surface
17b of the vibrating reed 15 correspond to front surfaces and rear
surfaces of the first vibrating arms 26a, 26b, front surfaces and
rear surfaces of the second vibrating arms 27a, 27b, and front
surfaces and rear surfaces of the third vibrating arms 28a, 28b,
respectively. The front surface 17a and the rear surface 17b of the
vibrating reed 15 specify the vibration directions excited by drive
signals, i.e., the excitation directions of the second vibrating
arms 27a, 27b as will be described later.
[0051] The pair of first vibrating arms 26a, 26b extend from the
base part 25 in a first direction D1. The first vibrating arms 26a,
26b are cantilevered by the base part 25. The first vibrating arms
26a, 26b extend in parallel to each other. The first vibrating arms
26a, 26b are formed in plane symmetry with respect to a symmetry
surface 29 containing the center of gravity of the base part 25 and
being orthogonal to the first and second reference planes RP1, RP2.
Here, the pair of first vibrating arms 26a, 26b function as a pair
of detecting arms. The base part 25 has predetermined rigidity.
[0052] The pair of second vibrating arms 27a, 27b extend from the
base part 25 in a second direction D2. The second direction D2 is
opposite to the first direction D1. The second vibrating arms 27a,
27b are cantilevered by the base part 25. The second vibrating arms
27a, 27b extend in parallel to each other. The second vibrating
arms 27a, 27b are formed in plane symmetry with respect to the
symmetry surface 29 containing the center of gravity of the base
part 25 and being orthogonal to the first and second reference
planes RP1, RP2. Here, the pair of second vibrating arms 27a, 27b
function as a pair of driving arms.
[0053] The pair of third vibrating arms 28a, 28b extend from the
base part 25 in the first direction D1. The third vibrating arms
28a, 28b are cantilevered by the base part 25. The third vibrating
arms 28a, 28b extend in parallel to each other. The third vibrating
arms 28a, 28b are formed in plane symmetry with respect to the
symmetry surface 29 containing the center of gravity of the base
part 25 and being orthogonal to the first and second reference
planes RP1, RP2. Here, the pair of third vibrating arms 28a, 28b
function as a pair of adjustment vibrating arms. The pair of
detecting arms are provided in a space between the adjustment
vibrating arms.
[0054] The main body 17 of the vibrating reed 15 has at least a
pair of first suspended arms 32a, 32b and a pair of second
suspended arms 33a, 33b. Here, the pair of first suspended arms
32a, 32b are partitioned in the main body 17. The first suspended
arms 32a, 32b extend from the fixing part 19 in the first direction
D1 on the sides of the pair of second vibrating arms 27a, 27b,
respectively. The ends of the first suspended arms 32a, 32b are
respectively connected to first connecting parts 34 of the base
part 25. The two first connecting parts 34 are located on the sides
of the pair of second vibrating arms 27a, 27b.
[0055] The second suspended arms 33a, 33b extend from the fixing
part 19 in the first direction D1 on the sides of the pair of
second vibrating arms 27a, 27b and the pair of first suspended arms
32a, 32b, respectively. The ends of the second suspended arms 33a,
33b are connected to second connecting parts 35 of the base part
25. The second connecting parts 35 are located at the downstream of
the first connecting parts 34 in the first direction D1.
[0056] As shown in FIG. 3, the conducting film 18 forms two pairs
of first drive electrodes 41a, 41b and two pairs of second drive
electrodes 42a, 42b. The first pair of first drive electrodes 41a
are fixed to one second vibrating arm 27a. The first drive
electrodes 41a spread on the side surfaces of the second vibrating
arm 27a. The second vibrating arm 27a is sandwiched between the
first drive electrodes 41a. The first drive electrodes 41a are
connected to each other at the free end side of the second
vibrating arm 27a. The second pair of first drive electrodes 41b
are fixed to the other second vibrating arm 27b. The first drive
electrodes 41b spread on the front surface 17a and the rear surface
17b of the second vibrating arm 27b. The second vibrating arm 27b
is sandwiched between the first drive electrodes 41b. The second
pair of first drive electrodes 41b are connected to the first pair
of first drive electrodes 41a in the base part 25.
[0057] The first pair of second drive electrodes 42a are fixed to
the one second vibrating arm 27a. The second drive electrodes 42a
spread on the front surface 17a and the rear surface 17b of the
second vibrating arm 27a. The second vibrating arm 27a is
sandwiched between the second drive electrodes 42a. The second pair
of second drive electrodes 42b are fixed to the other second
vibrating arm 27b. The second drive electrodes 42b spread on the
side surfaces of the second vibrating arm 27b. The second vibrating
arm 27b is sandwiched between the second drive electrodes 42b. The
second drive electrodes 42b are connected to each other at the free
end side of the second vibrating arm 27b. The second pair of second
drive electrodes 42b are connected to the first pair of second
drive electrodes 42a in the base part 25. When electric fields are
applied between the first drive electrodes 41a, 41b and the second
drive electrodes 42a, 42b, the second vibrating arms 27a, 27b are
deformed.
[0058] The conducting film 18 forms a first driving wire 43 and a
second driving wire 44. The first driving wire 43 is fixed to one
first suspended arm 32a. The first driving wire 43 extends over the
entire length of the first suspended arm 32a on the first suspended
arm 32a. The first driving wire 43 is connected to the first drive
electrodes 41a, 41b. The second driving wire 44 is fixed to the
other first suspended arm 32b. The second driving wire 44 extends
over the entire length of the first suspended arm 32b on the first
suspended arm 32b. The second driving wire 44 is connected to the
second drive electrodes 42a, 42b.
[0059] As shown in FIG. 4, the group of connecting terminals 21
include a first driving terminal 45 and a second driving terminal
46. The first driving terminal 45 and the second driving terminal
46 are respectively fixed to the rear surface 17b of the fixing
part 19. The first driving terminal 45 is connected to the first
driving wire 43. The second driving terminal 46 is connected to the
second driving wire 44. Drive signals may be supplied from the
first driving terminal 45 and the second driving terminal 46 to the
first drive electrodes 41a, 41b and the second drive electrodes
42a, 42b.
[0060] The conducting film 18 forms two sets of pairs of first
detection electrodes (signal electrodes 47a and ground electrodes
47b) and two sets of pairs of second detection electrodes (signal
electrodes 48a and ground electrodes 48b). As shown in FIG. 5, the
signal electrode 47a and the ground electrode 47b of the pair of
first detection electrodes are fixed to one first vibrating arm
26a. The signal electrode 47a of the pair of first detection
electrodes extends from the base of the first vibrating arm 26a
toward the free end on the front surface 17a of the first vibrating
arm 26a. The ground electrode 47b of the pair of first detection
electrodes extends from the base of the first vibrating arm 26a
toward the free end on the front surface 17a of the first vibrating
arm 26a.
[0061] The signal electrode 48a and the ground electrode 48b of the
pair of second detection electrodes are fixed to the other first
vibrating arm 26b. The signal electrode 48a of the pair of second
detection electrodes extends from the base of the first vibrating
arm 26b toward the free end on the front surface 17a of the first
vibrating arm 26b. The ground electrode 48b of the pair of first
detection electrodes extends from the base of the first vibrating
arm 26b toward the free end on the front surface 17a of the first
vibrating arm 26b.
[0062] The conducting film 18 forms two sets of pairs of first
adjustment electrodes 49 and two sets of pairs of second adjustment
electrodes 51. The pair of first adjustment electrodes 49 are fixed
to the third vibrating arm 28a. The pair of first adjustment
electrodes 49 include a first electrode piece 49a and a pair of
second electrode pieces 49b. The first electrode piece 49a is
provided on a first side surface 52 of the third vibrating arm 28a.
The first side surface 52 is specified in parallel to the symmetry
surface 29 and connects the front surface (first surface) 17a and
the rear surface (second surface) 17b of the third vibrating arm
28a to each other. The first electrode piece 49a extends from the
base of the third vibrating arm 28a toward the free end over the
entire length of the third vibrating arm 28a.
[0063] One second electrode piece 49b is provided on the front
surface 17a of the third vibrating arm 28a. The second electrode
piece 49b extends from the base of the third vibrating arm 28a
toward the free end over the entire length of the third vibrating
arm 28a. The second electrode piece 49b is adjacent to the first
electrode piece 49a with the first side surface 52 and the edge
line of the front surface 17a in between. A gap is partitioned
between the first electrode piece 49a and the second electrode
piece 49b along the edge line. Currents are drawn from the first
electrode piece 49a and the second electrode piece 49b in response
to the deformation of the third vibrating arm 28a.
[0064] The pair of second adjustment electrodes 51 are similarly
connected to the third vibrating arm 28a. The pairs of second
adjustment electrodes 51 include a third electrode piece 51a and a
pair of fourth electrode pieces 51b. The third electrode piece 51a
is provided on a second side surface 53 of the third vibrating arm
28a. The second side surface 53 is specified in parallel to the
symmetry surface 29 and connects the front surface (first surface)
17a and the rear surface (second surface) 17b of the third
vibrating arm 28a to each other. The second side surface 53 is
located at the opposite side (rear side) to the first side surface
52. The third electrode piece 51a extends from the base of the
third vibrating arm 28a toward the free end over the entire length
of the third vibrating arm 28a. The third electrode piece 51a is
opposed to the first electrode piece 49a with the third vibrating
arm 28a in between.
[0065] One fourth electrode piece 51b is provided on the front
surface 17a of the third vibrating arm 28a. The fourth electrode
piece 51b extends from the base of the third vibrating arm 28a
toward the free end over the entire length of the third vibrating
arm 28a. The fourth electrode piece 51b is adjacent to the third
electrode piece 51a with the second side surface 53 and the edge
line of the front surface 17a in between. A gap is partitioned
between the third electrode piece 51a and the fourth electrode
piece 51b along the edge line. Currents are drawn from the third
electrode piece 51a and the fourth electrode piece 51b in response
to the deformation of the third vibrating arm 28a.
[0066] Similarly, the pair of first adjustment electrodes 49 and
the pair of second adjustment electrodes 51 are fixed to the other
third vibrating arm 28b. For fixing, the first side surface 52 and
the second side surface 53 are specified on the third vibrating arm
28b like the third vibrating arm 28a. The first electrode piece 49a
and the third electrode piece 51a are fixed to the first side
surface 52 and the second side surface 53 of the third vibrating
arm 28b, respectively. The second electrode piece 49b and the
fourth electrode piece 51b are fixed to the front surface (first
surface) 17a of the third vibrating arm 28b.
[0067] The conducting film 18 forms a first detection wire 55 and a
second detection wire 56. The first detection wire 55 and the
second detection wire 56 are fixed to the base 25 and one second
suspended arm 33a. The first electrode piece 49a and the fourth
electrode piece 51b of the third vibrating arm 28a are electrically
connected to the first detection wire 55. The second electrode
piece 49b and the third electrode piece 51a are electrically
connected to the second detection wire 56. Similarly, the
conducting film 18 forms a third detection wire 57 and a fourth
detection wire 58. The third detection wire 57 and the fourth
detection wire 58 are fixed to the base 25 and the other second
suspended arm 33b. The first electrode piece 49a and the fourth
electrode piece 51b of the third vibrating arm 28b are electrically
connected to the third detection wire 57. The second electrode
piece 49b and the third electrode piece 51a are electrically
connected to the fourth detection wire 58.
[0068] As shown in FIG. 6, the signal electrode 47a and the ground
electrode 47b of the pair of first detection electrodes are
similarly provided on the rear surface 17b of the first vibrating
arm 26a. The signal electrode 47a and the ground electrode 47b
extend from the base of the first vibrating arm 26a toward the free
end. The signal electrode 47a on the rear surface 17b may be
connected to the signal electrode 47a on the front surface 17a at
the free end of the first vibrating arm 26a. The ground electrode
47b on the rear surface 17b may be connected to the ground
electrode 47b on the front surface 17a in the base part 25.
Currents are drawn from the signal electrodes 47a and the ground
electrodes 47b in response to the deformation of the first
vibrating arm 26a.
[0069] The signal electrode 48a and the ground electrode 48b are
similarly fixed to the rear surface 17b of the other first
vibrating arm 26b. The signal electrode 48a and the ground
electrode 48b extend from the base of the first vibrating arm 26b
toward the free end. The signal electrode 48a on the rear surface
17b may be connected to the signal electrode 48a on the front
surface 17a at the free end of the first vibrating arm 26b. The
ground electrode 48b on the rear surface 17b may be connected to
the ground electrode 48b on the front surface 17a in the base part
25. Currents are drawn from the signal electrodes 48a and the
ground electrodes 48b in response to the deformation of the first
vibrating arm 26b.
[0070] The other second electrode piece 49b is similarly provided
on the rear surface 17b of the third vibrating arm 28a. The second
electrode piece 49b extends from the base of the third vibrating
arm 28a toward the free end over the entire length of the third
vibrating arm 28a. The second electrode piece 49b is adjacent to
the first electrode piece 49a with the first side surface 52 and
the edge line of the rear surface 17b in between. A gap is
partitioned between the first electrode piece 49a and the second
electrode piece 49b along the edge line. Currents are drawn from
the first electrode piece 49a and the second electrode piece 49b in
response to the deformation of the third vibrating arm 28a.
Similarly, the other fourth electrode piece 51b is provided on the
rear surface 17b of the third vibrating arm 28a. The fourth
electrode piece 51b extends from the base of the third vibrating
arm 28a toward the free end over the entire length of the third
vibrating arm 28a. The fourth electrode piece 51b is adjacent to
the third electrode piece 51a with the second side surface 53 and
the edge line of the rear surface 17b in between. A gap is
partitioned between the third electrode piece 51a and the fourth
electrode piece 51b along the edge line. Currents are drawn from
the third electrode piece 51a and the fourth electrode piece 51b in
response to the deformation of the third vibrating arm 28a.
[0071] The group of connecting terminals 21 include a pair of first
detection terminals (a signal terminal 59a and a ground terminal
59b) and a pair of second detection terminals (a signal terminal
61a and a ground terminal 61b). The signal terminal 59a and the
ground terminal 59b of the first detection terminal and the signal
terminal 61a and the ground terminal 61b of the second detection
terminal are fixed to the fixing part 19. The signal terminal 59a
of the first detection terminal is electrically connected to the
first detection wire 55. The ground terminal 59b of the first
detection terminal is electrically connected to the second
detection wire 56. The signal terminal 61a of the second detection
terminal is electrically connected to the third detection wire 57.
The ground terminal 61b of the second detection terminal is
electrically connected to the fourth detection wire 58. The ground
terminal 59b is provided between the signal terminal 59a and the
first driving terminal 45. Similarly, the ground terminal 61b is
provided between the signal terminal 61a and the second driving
terminal 46.
(2) Movement of Gyro Sensor according to First Embodiment
[0072] Next, the movement of the gyro sensor 11 will be briefly
explained. As shown in FIG. 7, for detection of an angular
velocity, vibration is excited in the second vibrating arms 27a,
27b. For excitation of vibration, drive signals are input from the
first driving terminal 45 and the second driving terminal 46 to the
vibrating reed 15. As a result, electric fields act on the main
body 17 of the vibrating reed 15 between the first drive electrodes
41a, 41b and the second drive electrodes 42a, 42b. When a waveform
with a specific frequency is input, the second vibrating arms 27a,
27b flexurally vibrate between the first reference plane RP1 and
the second reference plane RP2. They move repeatedly away from each
other and close to each other.
[0073] When angular velocity motion is applied to the gyro sensor
11, as shown in FIG. 8, the vibration directions of the second
vibrating arms 27a, 27b change due to action of Coriolis force. The
so-called walk-mode excitation is caused. Concurrently, a new force
component is generated in parallel to the symmetry surface 29 in
response to the Coriolis force. The second vibrating arms 27a, 27b
flexurally vibrate in parallel to the symmetry surface 29. The
second vibrating arms 27a, 27b swing around the center of gravity
of the vibration.
[0074] The walk-mode excitation of the second vibrating arms 27a,
27b propagates from the base part 25 to the first vibrating arms
26a, 26b. As a result, motion of the first vibrating arms 26a, 26b
is caused according to the force component in parallel to the
symmetry surface 29. The first vibrating arms 26a, 26b flexurally
move in parallel to the symmetry surface 29. The first vibrating
arms 26a, 26b swing around the center of gravity of the vibration.
In response to the flexural motion, electric fields are generated
in the first vibrating arms 26a, 26b according to the piezoelectric
effect, and electric charge is generated. The flexural motion of
the first vibrating arm 26a produces a potential difference between
the signal electrode 47a and the ground electrode 47b of the pair
of first detection electrodes. Similarly, the flexural motion of
the first vibrating arm 26b produces a potential difference between
the signal electrode 48a and the ground electrode 48b of the pair
of second detection electrodes.
[0075] The walk-mode excitation of the second vibrating arms 27a,
27b propagates from the base part 25 to the third vibrating arms
28a, 28b. As a result, the motion of the third vibrating arms 28a,
28b is caused. In response to the motion, electrical signals are
respectively output from the pairs of first adjustment electrodes
49 and the pairs of second adjustment electrodes 51.
[0076] As shown in FIGS. 9A to 9C, when the shapes of the first
vibrating arms 26a, 26b deviate from the designed shapes according
to the processing errors, for example, in the output signals from
the first vibrating arms 26a, 26b, components of vibration leakage
are superimposed on the force components of the Coriolis force.
Concurrently, the electrical signals of the pair of first
adjustment electrodes 49 and the electrical signals of the pair of
second adjustment electrodes 51 are superimposed on the output
signals of the first vibrating arms 26a, 26b. The magnitudes of the
electrical signals are adjusted. As a result of the adjustment, the
electrical signals of the pairs of first and second adjustment
electrodes 49, 51 may cancel out the components of vibration
leakage. Accordingly, the S/N-ratio of the output signals is
improved. For adjustment of the electrical signals, the shapes of
the pair of first adjustment electrodes 49 and the pair of second
adjustment electrodes 51 are adjusted in advance. The volume of the
piezoelectric member intervening between the first electrode piece
49a and the second electrode pieces 49b and the distances between
the first electrode piece 49a and the second electrode pieces 49b
are adjusted. The volume of the piezoelectric member intervening
between the third electrode piece 51a and the fourth electrode
pieces 51b and the distances between the third electrode piece 51a
and the fourth electrode pieces 51b are adjusted. The formation of
cuts in the first vibrating arms 26a, 26b, the second vibrating
arms 27a, 27b, and the third vibrating arms 28a, 28b may be
avoided. The reduction in mechanical strength may be avoided. The
cuts are not formed, and improvement in processing accuracy is not
necessarily required.
[0077] In addition, the electrical signals of the pair of first
adjustment electrodes 49 and the electrical signals of the pair of
second adjustment electrodes 51 are in anti-phase with each other,
and the magnitudes of the electrical signals may be adjusted
according to the relative relations between the pair of first
adjustment electrodes 49 and the pair of second adjustment
electrodes 51. Therefore, as clearly seen from FIGS. 9A to 9C and
10A to 10C, whether the phase of the vibration leakage is in-phase
or anti-phase with the output signals of the first vibrating arms
26a, 26b, the components of vibration leakage may be cancelled out.
When the electrical signals of the pair of first adjustment
electrodes 49 and the electrical signals of the pair of second
adjustment electrodes 51 are cancelled out by each other, the
influence on the output signals of the first vibrating arms 26a,
26b by the electrical signals may be eliminated as shown in FIGS.
11A and 11B.
(3) Method of Manufacturing Gyro Sensor according to First
Embodiment
[0078] For manufacture of the gyro sensor 11, the vibrating reed 15
is manufactured. The main body 17 of the vibrating reed 15 is cut
out from quartz. The conducting film 18 is formed on the main body
17. The conducting film 18 is formed in a designed pattern. For
formation of the conducting film 18, for example, a
photolithography technology may be used.
[0079] The container 12 is prepared. The IC chip 16 is fixed within
the container main body 13. Subsequently, the vibrating reed 15 is
fixed within the container main body 13. The group of connecting
terminals 21 are bonded to the group of connecting terminals 22.
The first and second driving terminals 45, 46, the first detection
terminals 59a, 59b, and the second detection terminals 61a, 61b are
respectively received by corresponding connecting terminals. Thus,
the vibrating reed 15 is electrically connected to the IC chip
16.
[0080] Here, tuning of the gyro sensor 11 is performed. In the
tuning, a control signal is supplied to the IC chip 16. The IC chip
16 starts detection operation of the angular velocity. As described
above, vibration is excited in the second vibrating arms 27a, 27b.
When no angular velocity motion acts, no Coriolis force is
generated in the second vibrating arms 27a, 27b. In this regard, if
the angular velocity="0" is detected in the gyro sensor 11, the
opening of the container main body 13 is air-tightly covered by the
lid member 14. The internal space of the container 12 is sealed.
The manufacture of the gyro sensor 11 is completed.
[0081] If the angular velocity="0" is not detected in the gyro
sensor 11, vibration leakage is assumed. In this case, the shapes
of the second electrode pieces 49b of the pairs of first adjustment
electrodes 49 and the fourth electrode pieces 51b of the pairs of
second adjustment electrodes 51 are adjusted in response to the
amount of measured electric charge. For example, parts of the
electrode pieces 49b, 51b are removed or cut off with a laser. As a
result, laser signature is formed around the electrode pieces 49b,
51b. As a result of the adjustment of the second electrode pieces
49b and the fourth electrode pieces 51b, if the angular
velocity="0" is not detected in the gyro sensor 11, the opening of
the container main body 13 is air-tightly covered by the lid member
14. The internal space of the container 12 is sealed. The
manufacture of the gyro sensor 11 is completed.
(4) Gyro Sensor according to Second Embodiment
[0082] In the gyro sensor 11 according to the second embodiment,
for the vibrating reed 15, third vibrating arms 63 are used in
place of the above described third vibrating arms 28a, 28b. As
shown in FIG. 12, a first groove 64 is formed on the front surface
(first surface) 17a of the third vibrating arm 63 and a second
groove 65 is formed on the rear surface (second surface) 17b of the
third vibrating arm 63. The first groove 64 and the second groove
65 extend from the base of the third vibrating arm 63 toward the
free end in the longitudinal direction of the third vibrating arm
63. The first groove 64 and the second groove 65 may be formed as
long grooves extending over the entire length of the third
vibrating arm 63.
[0083] The first groove 64 has a first wall surface 66a and a
second wall surface 66b. The first wall surface 66a and the second
wall surface 66b face each other. The first wall surface 66a
sandwiches the piezoelectric member of the third vibrating arm 63
between the first side surface 52 and itself. The second wall
surface 66b sandwiches the piezoelectric member of the third
vibrating arm 63 between the second side surface 53 and itself. The
first wall surface 66a and the second wall surface 66b may spread
in parallel to the symmetry surface 29.
[0084] The second groove 65 has a third wall surface 67a and a
fourth wall surface 67b. The third wall surface 67a and the fourth
wall surface 67b face each other. The third wall surface 67a
sandwiches the piezoelectric member of the third vibrating arm 63
between the first side surface 52 and itself. The fourth wall
surface 67b sandwiches the piezoelectric member of the third
vibrating arm 63 between the second side surface 53 and itself. The
third wall surface 67a and the fourth wall surface 67b may spread
in parallel to the symmetry surface 29.
[0085] To the individual third vibrating arms 63, a pair of first
adjustment electrodes 68 and a pair of second adjustment electrodes
69 are fixed. The pair of first adjustment electrodes 68 include a
first electrode piece 68a and a pair of second electrode pieces
68b. The first electrode piece 68a is provided on the first side
surface 52 of the third vibrating arm 63. The first electrode piece
68a extends from the base of the third vibrating arm 63 toward the
free end over the entire length of the third vibrating arm 68. The
first electrode piece 68a is electrically connected to the first
detection wire 55 or the third detection wire 57.
[0086] One second electrode piece 68b is provided on the first wall
surface 66a inside of the first groove 64. The second electrode
piece 68b extends from the base of the third vibrating arm 63
toward the free end over the entire length of the first groove 64.
The other second electrode piece 68b is provided on the third wall
surface 67a inside of the second groove 65. The second electrode
piece 68b extends from the base of the third vibrating arm 63
toward the free end over the entire length of the second groove 65.
The second electrode piece 68b is electrically connected to the
second detection wire 56 or the fourth detection wire 58.
[0087] The pair of second adjustment electrodes 69 include a third
electrode piece 69a and a pair of fourth electrode pieces 69b. The
third electrode piece 69a is provided on the second side surface 53
of the third vibrating arm 63. The third electrode piece 69a
extends from the base of the third vibrating arm 63 toward the free
end over the entire length of the third vibrating arm 63. The third
electrode piece 69a is electrically connected to the second
detection wire 56 or the fourth detection wire 58.
[0088] One fourth electrode piece 69b is provided on the second
wall surface 66b inside of the first groove 64. The fourth
electrode piece 69b extends from the base of the third vibrating
arm 63 toward the free end over the entire length of the first
groove 64. The other fourth electrode piece 69b is provided on the
fourth wall surface 67b inside of the second groove 65. The fourth
electrode piece 69b extends from the base of the third vibrating
arm 63 toward the free end over the entire length of the second
groove 65. The fourth electrode piece 69b is electrically connected
to the first detection wire 55 or the third detection wire 57.
[0089] The rest of the configuration may be formed to be the same
as the configuration of the above described first embodiment. The
equal configurations and structures to those of the above described
first embodiment have the same reference signs and their detailed
explanation will be omitted.
[0090] When the vibration excited by the drive signal is
transmitted to the third vibrating arm 63, the second side surface
53 expands at contraction of the first side surface 52 and the
second side surface 53 contracts at expansion of the first side
surface 52. As a result, the pair of second adjustment electrodes
69 may output electrical signals in anti-phase with those of the
pair of first adjustment electrodes 68. In the second embodiment,
the piezoelectric member is sandwiched between the first electrode
piece 68a and the second electrode pieces 68b, the piezoelectric
member is sandwiched between the third electrode piece 69a and the
fourth electrode pieces 69b, and thus, the larger output signals
may be obtained in the pair of first adjustment electrodes 68 and
the pair of second adjustment electrodes 69 than those of the above
described pair of first adjustment electrodes 49 and pair of second
adjustment electrodes 51. The adjustment range of the vibration
leakage may be wider. The yield may be improved.
(5) Gyro Sensor according to Third Embodiment
[0091] As shown in FIGS. 13A and 13B, in the gyro sensor 11
according to the third embodiment, a vibrating reed 15a includes a
pair of first vibrating arms 71a, 71b in place of the above
described first vibrating arms 26a, 26b. In the first vibrating arm
71a, the second side surface 53 and the front surface 17a are
connected to each other at a first step 72. Similarly, the side
surface 53 and the rear surface 17b are connected to each other at
a second step 73. The first step 72 and the second step 73 extend
from the base of the first vibrating arm 71a toward the free end
over the entire length of the first vibrating arm 71a, for example.
The first step 72 includes a step surface 72a specifying an edge
line between the second side surface 53 and itself and a vertical
surface 72b crossing the step surface 72a and specifying an edge
line between the front surface 17a and itself. The piezoelectric
member of the first vibrating arm 71a is sandwiched between the
vertical surface 72b and the first side surface 52. Similarly, the
second step 73 includes a step surface 73a specifying an edge line
between the second side surface 53 and itself and a vertical
surface 73b crossing the step surface 73a and specifying an edge
line between the rear surface 17b and itself. The piezoelectric
member of the first vibrating arm 71a is sandwiched between the
vertical surface 73b and the first side surface 52. The
piezoelectric member of the first vibrating arm 71a is sandwiched
between the step surfaces 72a, 73a. The two first vibrating arms
71a, 71b are formed in the same shape. The step surfaces 72a, 73a
may spread in parallel to the front surface 17a and the rear
surface 17b. The vertical surfaces 72b, 73b may spread in parallel
to the symmetry surface 29.
[0092] In the individual first vibrating arms 71a, 71b, the
conducting film 18 forms a pair of first detection electrodes and a
pair of second detection electrodes. In one first vibrating arm
71a, a first signal electrode 74 of the pair of first detection
electrodes is fixed to the first step 72. The first signal
electrode 74 covers the step surface 72a and the vertical surface
72b of the first step 72. The first signal electrode 74 extends
from the base of the first vibrating arm 71a toward the free end
over the entire length of the first step 72, for example. A second
signal electrode 75 of the pair of second detection electrodes is
fixed to the second step 73. The second signal electrode 75 covers
the step surface 73a and the vertical surface 73b of the second
step 73. The second signal electrode 75 extends from the base of
the first vibrating arm 71a toward the free end over the entire
length of the second step 73, for example. The pair of first
detection electrodes and the pair of second detection electrodes
have a ground electrode 76 in common. The ground electrode 76 is
fixed to the first side surface 52. The ground electrode 76 covers
the first side surface 52. The ground electrode 76 extends from the
base of the first vibrating arm 71a toward the free end over the
entire length of the first vibrating arm 71a, for example.
Accordingly, the piezoelectric member of the first vibrating arm
71a is sandwiched between the first signal electrode 74 and the
ground electrode 76 and sandwiched between the second signal
electrode 75 and the ground electrode 76.
[0093] In the other first vibrating arm 71b, a first signal
electrode 74 of the pair of first detection electrodes is fixed to
the second step 73. The first signal electrode 74 covers the step
surface 73a and the vertical surface 73b of the second step 73. The
first signal electrode 74 extends from the base of the first
vibrating arm 71b toward the free end over the entire length of the
second step 73, for example. A second signal electrode 75 of the
pair of second detection electrodes is fixed to the first step 72.
The second signal electrode 75 covers the step surface 72a and the
vertical surface 72b of the first step 72. The second signal
electrode 75 extends from the base of the first vibrating arm 71b
toward the free end over the entire length of the first step 72,
for example. The pair of first detection electrodes and the pair of
second detection electrodes have a ground electrode 76 in common.
The ground electrode 76 is fixed to the first side surface 52. The
ground electrode 76 covers the first side surface 52. The ground
electrode 76 extends from the base of the first vibrating arm 71b
toward the free end over the entire length of the first vibrating
arm 71b, for example. Accordingly, the piezoelectric member of the
first vibrating arm 71b is sandwiched between the second signal
electrode 75 and the ground electrode 76 and sandwiched between the
first signal electrode 74 and the ground electrode 76.
[0094] As shown in FIG. 14, the first signal electrode 74 of the
first vibrating arm 71a is connected to the first detection wire
55. For the connection, the conducting film 18 forms a first wire
77 on the base part 25. The first wire 77 connects the first signal
electrode 74 of the first vibrating arm 71a to the fourth electrode
piece 51b of the third vibrating arm 28a on the front surface
17a.
[0095] The second signal electrode 75 of the first vibrating arm
71b is connected to the third detection wire 57. For the
connection, the conducting film 18 forms a second wire 78 on the
base part 25. The second wire 78 connects the second signal
electrode 75 of the first vibrating arm 71b to the fourth electrode
piece 51b of the third vibrating arm 28b on the front surface
17a.
[0096] As shown in FIG. 15, the second signal electrode 75 of the
first vibrating arm 71a is connected to the third detection wire
57. For the connection, the conducting film 18 forms a third wire
79 on the base part 25. The third wire 79 extends from the rear
surface 17b to the front surface 17a between the first vibrating
arm 71b and the third vibrating arm 28b. The third wire 79 is
connected to the second wire 78.
[0097] The first signal electrode 74 of the first vibrating arm 71b
is connected to the first detection wire 55. For the connection,
the conducting film 18 forms a fourth wire 81 on the base part 25.
The fourth wire 81 extends from the rear surface 17b to the front
surface 17a between the first vibrating arms 71a and 71b. The
fourth wire 81 is connected to the first wire 77.
[0098] The ground electrodes 76 of the first vibrating arms 71a,
71b are connected to the second detection wire 56 and the fourth
detection wire 58. Here, the second detection wire 56 and the
fourth detection wire 58 may be connected to each other. As a
result, the ground electrodes 76 may be connected to the ground
terminal 59b of the first detection terminal and the ground
electrode 61b of the second detection terminal. By employing the
first vibrating arms 71a, 71b, the detection sensitivity of the
first vibrating arms 71a, 71b increases. The S/N-ratio is
improved.
(6) Gyro Sensor according to Fourth Embodiment
[0099] As shown in FIG. 16, in the gyro sensor 11 according to the
fourth embodiment, a vibrating reed 15b includes a pair of first
adjustment electrodes 82 and a pair of second adjustment electrodes
83 in place of the above described pair of first adjustment
electrodes 49 and pair of second adjustment electrodes 51. The pair
of first adjustment electrodes 82 include a first electrode piece
82a and a pair of second electrode pieces 82b. The first electrode
piece 82a is provided on the front surface 17a of the third
vibrating arm 28a. The first electrode piece 82a extends from the
base of the third vibrating arm 28a toward the free end over the
entire length of the third vibrating arm 28a.
[0100] The second electrode pieces 82b are respectively provided on
the first side surface 52 and the second side surface 53 of the
third vibrating arm 28a. The second electrode pieces 82b extend
from the base of the third vibrating arm 28a toward the free end
over the entire length of the third vibrating arm 28a. One second
electrode piece 82b is adjacent to the first electrode piece 82a
with the first side surface 52 and the edge line of the front
surface 17a in between. The other second electrode piece 82b is
adjacent to the first electrode piece 82a with the second side
surface 53 and the edge line of the front surface 17a in between.
Gaps are respectively partitioned between the first electrode piece
82a and the second electrode pieces 82b along the edge lines.
Currents are drawn from the first electrode piece 82a and the
second electrode pieces 82b in response to the deformation of the
third vibrating arm 28a.
[0101] The pair of second adjustment electrodes 83 include a third
electrode piece 83a and a pair of fourth electrode pieces 83b. The
first electrode piece 83a is provided on the rear surface 17b of
the third vibrating arm 28a. The third electrode piece 83a extends
from the base of the third vibrating arm 28a toward the free end
over the entire length of the third vibrating arm 28a. The fourth
electrode pieces 83b are respectively provided on the first side
surface 52 and the second side surface 53 of the third vibrating
arm 28a. The fourth electrode pieces 83b extend from the base of
the third vibrating arm 28a toward the free end over the entire
length of the third vibrating arm 28a. One fourth electrode piece
83b is adjacent to the third electrode piece 83a with the first
side surface 52 and the edge line of the rear surface 17b in
between. The other fourth electrode piece 83b is adjacent to the
third electrode piece 83a with the second side surface 53 and the
edge line of the rear surface 17b in between. Gaps are respectively
partitioned between the third electrode piece 83a and the fourth
electrode pieces 83b along the edge lines. Currents are drawn from
the third electrode piece 83a and the fourth electrode pieces 83b
in response to the deformation of the third vibrating arm 28a.
Similarly, the pair of first adjustment electrodes 82 and the pair
of second adjustment electrodes 83 are fixed to the other third
vibrating arm 28b.
[0102] As shown in FIG. 17, the conducting film 18 forms a first
detection wire 84 and a second detection wire 85. The first
detection wire 84 and the second detection wire 85 are fixed to the
base part 25 and one second suspended arm 33a. The first electrode
piece 82a of the third vibrating arm 28a and the signal electrode
47a of the first vibrating arm 26a are electrically connected the
first detection wire 84. The second electrode piece 82b and the
ground electrode 47b of the first vibrating arm 26a are
electrically connected the second detection wire 85. Similarly, the
conducting film 18 forms a third detection wire 86 and a fourth
detection wire 87. The third detection wire 86 and the fourth
detection wire 87 are fixed to the base part 25 and the other
second suspended arm 33b. The first electrode piece 82a of the
third vibrating arm 28b and the signal electrode 48a of the first
vibrating arm 26b are electrically connected the third detection
wire 86. The second electrode piece 82b and the ground electrode
48b of the first vibrating arm 26b are electrically connected the
fourth detection wire 87.
[0103] As shown in FIG. 18, the fourth electrode piece 83b of the
third vibrating arm 28a and the signal electrode 47a of the first
vibrating arm 26a are electrically connected to the first detection
wire 84. The first detection wire 84 is electrically connected to
the signal terminal 59a of the first detection terminal. The third
electrode piece 83a of the third vibrating arm 28a and the ground
electrode 47b of the first vibrating arm 26a are electrically
connected to the second detection wire 85. The second detection
wire 85 is electrically connected to the ground terminal 59b of the
first detection terminal. Similarly, the fourth electrode piece 83b
of the third vibrating arm 28b and the signal electrode 48a of the
first vibrating arm 26b are electrically connected to the third
detection wire 86. The third detection wire 86 is electrically
connected to the signal terminal 61a of the second detection
terminal. The third electrode piece 83a of the third vibrating arm
28b and the ground electrode 48b of the first vibrating arm 26b are
electrically connected to the fourth detection wire 87. The fourth
detection wire 87 is electrically connected to the ground terminal
61b of the second detection terminal.
[0104] As shown in FIGS. 19A to 19C, when the shapes of the first
vibrating arms 26a, 26b deviate from the designed shapes according
to the processing errors, for example, in the output signals from
the first vibrating arms 26a, 26b, components of vibration leakage
are superimposed on the force components of the Coriolis force.
Concurrently, the electrical signals of the pair of first
adjustment electrodes 82 and the electrical signals of the pair of
second adjustment electrodes 83 are superimposed on the output
signals of the first vibrating arms 26a, 26b. The magnitudes of the
electrical signals are adjusted. As a result of the adjustment, the
electrical signals of the pairs of first and second adjustment
electrodes 82, 83 may cancel out the components of vibration
leakage. Accordingly, the S/N-ratio of the output signals is
improved. For adjustment of the electrical signals, the shapes of
the pair of first adjustment electrodes 82 and the pair of second
adjustment electrodes 83 are adjusted in advance. The volume of the
piezoelectric member intervening between the first electrode piece
82a and the second electrode pieces 82b and the distances between
the first electrode piece 82a and the second electrode pieces 82b
are adjusted. The volume of the piezoelectric member intervening
between the third electrode piece 83a and the fourth electrode
pieces 83b and the distances between the third electrode piece 83a
and the fourth electrode pieces 83b are adjusted. Formation of cuts
in the first vibrating arms 26a, 26b, the second vibrating arms
27a, 27b, and the third vibrating arms 28a, 28b may be avoided. The
reduction in mechanical strength may be avoided. The cuts are not
formed, and the improvement in processing accuracy is not
necessarily required.
[0105] In addition, the electrical signals of the pair of first
adjustment electrodes 82 and the electrical signals of the pair of
second adjustment electrodes 83 are in anti-phase with each other,
and the magnitudes of the electrical signals may be adjusted
according to the relative relations between the pair of first
adjustment electrodes 82 and the pair of second adjustment
electrodes 83. Therefore, as clearly seen from FIGS. 19A to 19C and
20A to 20C, whether the phase of the vibration leakage is in-phase
or anti-phase with the output signals of the first vibrating arms
26a, 26b, the components of vibration leakage may be cancelled out.
When the electrical signals of the pair of first adjustment
electrodes 82 and the electrical signals of the pair of second
adjustment electrodes 83 are cancelled out by each other, the
influence on the output signals of the first vibrating arms 26a,
26b by the electrical signals may be eliminated like that as
described above.
(7) Gyro Sensor According to Fifth Embodiment
[0106] In the gyro sensor 11 according to the fifth embodiment, for
the vibrating reed 15, a third vibrating arm 88 is used in place of
the above described third vibrating arms 28a, 28b. As shown in FIG.
21, in the third vibrating arm 88, the front surface 17a and the
rear surface 17b are respectively connected to the first side
surface 52 at a first step 89 and a second step 91. Similarly, in
the third vibrating arm 88, the front surface 17a and the rear
surface 17b are respectively connected to the second side surface
53 at a third step 92 and a fourth step 93. The first to fourth
steps 89 to 93 extend from the base of the third vibrating arm 88
toward the free end over the entire length of the third vibrating
arm 88, for example.
[0107] The first step 89 includes a step surface 89a specifying an
edge line between the first side surface 52 and itself and a
vertical surface 89b crossing the step surface 89a and specifying
an edge line between the front surface 17a and itself. The second
step 91 includes a step surface 91a specifying an edge line between
the first side surface 52 and itself and a vertical surface 91b
crossing the step surface 91a and specifying an edge line between
the rear surface 17b and itself. The third step 92 includes a step
surface 92a specifying an edge line between the second side surface
53 and itself and a vertical surface 92b crossing the step surface
92a and specifying an edge line between the front surface 17a and
itself. The fourth step 93 includes a step surface 93a specifying
an edge line between the second side surface 53 and itself and a
vertical surface 93b crossing the step surface 93a and specifying
an edge line between the rear surface 17b and itself. A
piezoelectric member of the third vibrating arm 88 is sandwiched
between the vertical surfaces 89b, 92b. Similarly, the
piezoelectric member of the third vibrating arm 88 is sandwiched
between the vertical surfaces 91b, 93b. The second electrode pieces
82b of the first adjustment electrode 82 are respectively fixed to
the vertical surface 89b of the first step 89 and the vertical
surface 92b of the third step 92. The fourth electrode pieces 83b
of the second adjustment electrode 83 are respectively fixed to the
vertical surface 91b of the second step 91 and the vertical surface
93b of the fourth step 93.
(8) Gyro Sensor According to Sixth Embodiment
[0108] In the gyro sensor 11 according to the sixth embodiment, for
the vibrating reed 15, a third vibrating arm 94 is used in place of
the above described third vibrating arm 88. In the third vibrating
arm 94, as shown in FIG. 22, a first groove 95 and a second groove
96 are formed on the front surface 17a and the rear surface 17b,
respectively, in the above described third vibrating arm 88. The
first groove 95 and the second groove 96 extend from the base of
the third vibrating arm 94 toward the free end in the longitudinal
direction of the third vibrating arm 94. The first groove 95 and
the second groove 96 may be formed as long grooves extending over
the entire length of the third vibrating arm 94.
[0109] The first groove 95 has a first wall surface 95a and a
second wall surface 95b. The first wall surface 95a and the second
wall surface 95b face each other. The first wall surface 95a
sandwiches a piezoelectric member of the third vibrating arm 94
between the vertical surface 89b of the first step 89 and itself.
The second wall surface 95b sandwiches the piezoelectric member of
the third vibrating arm 94 between the vertical surface 92b of the
third step 92 and itself. The first wall surface 95a and the second
wall surface 95b may spread in parallel to the symmetry surface
29.
[0110] The second groove 96 has a third wall surface 96a and a
fourth wall surface 96b. The third wall surface 96a and the fourth
wall surface 96b face each other. The third wall surface 96a
sandwiches the piezoelectric member of the third vibrating arm 94
between the vertical surface 91b of the second step 91 and itself.
The fourth wall surface 96b sandwiches the piezoelectric member of
the third vibrating arm 94 between the vertical surface 93b of the
fourth step 93 and itself. The third wall surface 96a and the
fourth wall surface 96b may spread in parallel to the symmetry
surface 29.
[0111] The first electrode piece 82a of the pair of first
adjustment electrodes 82 is fixed to the first wall surface 95a and
the second wall surface 95b of the first groove 95. Therefore, the
piezoelectric member of the third vibrating arm 94 is sandwiched
between the first electrode piece 82a and the second electrode
pieces 82b. The third electrode piece 83a of the pair of second
adjustment electrodes 83 is fixed to the third wall surface 96a and
the fourth wall surface 96b. Therefore, the piezoelectric member of
the third vibrating arm 94 is sandwiched between the first
electrode piece 83a and the second electrode pieces 83b. The rest
of the configuration may be formed to be the same as the
configuration of the above described first embodiment. The equal
configurations and structures to those of the above described first
embodiment have the same reference signs and their detailed
explanation will be omitted.
[0112] When the vibration excited by the Coriolis force is
transmitted to the third vibrating arm 94, the rear surface 71b
expands at contraction of the front surface 17a and the rear
surface 17b contracts at expansion of the front surface 17a. As a
result, the pair of second adjustment electrodes 83 may output
electrical signals in anti-phase with those of the pair of first
adjustment electrodes 82. In the sixth embodiment, the
piezoelectric member is sandwiched between the first electrode
piece 82a and the second electrode pieces 82b, the piezoelectric
member is sandwiched between the third electrode piece 83a and the
fourth electrode pieces 83b, and thus, the larger output signals
may be obtained in the pair of first adjustment electrodes 82 and
the pair of second adjustment electrodes 83 than those of the above
described pair of first adjustment electrodes 82 and pair of second
adjustment electrodes 83. The adjustment range of the vibration
leakage may be wider. The yield may be improved.
(9) Gyro Sensor According to Seventh Embodiment
[0113] In the gyro sensor 11 according to the seventh embodiment, a
vibrating reed 15c is used in place of the above described
vibrating reed 15. As shown in FIG. 23, the vibrating reed 15c
includes a main body 101 having a tuning-fork shape. The main body
101 is formed in plane symmetry with respect to the symmetry
surface 29 containing the center of gravity of the main body 101
and orthogonal to the first and second reference planes RP1, RP2.
The main body 101 is formed using a non-piezoelectric material.
Here, the main body 101 is formed using silicon (Si), for example.
The main body 101 has abase part 102 and first vibrating arms 103a,
103b. The first vibrating arms 103a, 103b extend from the base part
102 in the same direction in parallel. The first vibrating arms
103a, 103b are cantilevered by the base part 102. For cantilever, a
fixing part 101a is partitioned at one end of the main body
101.
[0114] A pair of drive piezoelectric members 104a, 104b and a
detection piezoelectric member 105 are respectively stacked on
surfaces of the first vibrating arms 103a, 103b. The drive
piezoelectric members 104a, 104b and the detection piezoelectric
member 105 may be formed using piezoelectric zirconate titanate
(PZT), for example. For stacking of the drive piezoelectric members
104a, 104b and the detection piezoelectric member 105, a foundation
film 106 of a conducting material is formed on the surface of the
main body 101. The foundation film 106 may function as a common
ground electrode. Drive electrodes 107a, 107b and a detection
electrode 108 are fixed to the surfaces of the drive piezoelectric
members 104a, 104b and the detection piezoelectric member 105,
respectively. Accordingly, the drive piezoelectric members 104a,
104b are sandwiched between the drive electrodes 107a, 107b and the
foundation film 106. The detection piezoelectric member 105 is
sandwiched between the detection electrode 108 and the foundation
film 106.
[0115] A pair of drive terminals 109a, 109b, a pair of detection
terminals 111, and a ground terminal 112 are provided in the fixing
part 101a. One drive terminal 109a is connected to one drive
electrode 107a with respect to each of the first vibrating arms
103a, 103b. The other drive terminal 109b is connected to the other
drive electrode 107b with respect to each of the first vibrating
arms 103a, 103b. The detection terminal 111 is connected to the
detection electrode 108. The ground terminal 112 is connected to
the foundation film 106. Therefore, when drive signals are supplied
to the drive electrodes 107a, 107b on the first vibrating arms
103a, 103b in anti-phase with each other, the first vibrating arms
103a, 103b flexurally move between the first reference plane PR1
and the second reference plane PR2. They move repeatedly away from
and closer to each other.
[0116] The main body 101 further includes a pair of second
vibrating arms 113. The second vibrating arms 113 extend in
parallel to the first vibrating arms 103a, 103b. A pair of
adjustment piezoelectric members 114 are stacked on the surface of
the second vibrating arm 113. The adjustment piezoelectric members
114 extend in parallel to the symmetry surface 29 and to each
other. The adjustment piezoelectric members 114 may be formed in
line symmetry with respect to a center line 115 of the second
vibrating arm 113 in parallel to the symmetry surface 29. The
adjustment piezoelectric members 114 may be formed using PZT, for
example. For stacking of the adjustment piezoelectric members 114,
in the second vibrating arm 113, the foundation film 106 spreads on
the surface of the main body 101. The foundation film 106 functions
as a ground electrode. Electrode pieces 117, 118 are individually
provided on the surfaces of the respective adjustment piezoelectric
members 114. The electrode pieces 117, 118 may be formed in line
symmetry with respect to the center line 115. The electrode pieces
117, 118 are respectively in contact with the adjustment
piezoelectric members 114 in locations apart from the foundation
film 106. Here, the adjustment piezoelectric members 114 are
sandwiched between the electrode pieces 117, 118 and the foundation
film 106.
[0117] When the vibration excited by the drive signal is
transmitted to the second vibrating arm 113, the adjustment
piezoelectric member 114 contracts in the longitudinal direction of
the second vibrating arm 113 between the electrode piece 117 and
the foundation film 106, and the adjustment piezoelectric member
114 expands in the longitudinal direction of the second vibrating
arm 113 between the electrode piece 118 and the foundation film
106. Conversely, when the adjustment piezoelectric member 114
expands in the longitudinal direction of the second vibrating arm
113 between the electrode piece 117 and the foundation film 106,
the adjustment piezoelectric member 114 contracts in the
longitudinal direction of the second vibrating arm 113 between the
electrode piece 118 and the foundation film 106. As a result, the
electrode piece 117 and the electrode piece 118 may output
electrical signals in anti-phase with each other.
[0118] Like the above described configuration, the components of
vibration leakage contained in the output signals of the first
vibrating arms 103a, 103b may be at least partially cancelled out
by the electrical signals of the electrode pieces 117, 118. When
the electrical signals of the electrode pieces 117, 118 are
superimposed on the output signals of the first vibrating arms
103a, 103b, the S/N-ratio of the output signals is improved. In
addition, the electrical signal of the electrode piece 117 and the
electrical signal of the electrode piece 118 are in anti-phase with
each other, and thus, the magnitudes of the electrical signals may
be adjusted according to the relative relation between the
electrode pieces 117, 118. Therefore, whether the phase of
vibration leakage is in in-phase or anti-phase with the output
signals of the first vibrating arms 103a, 103b, the component of
the vibration leakage may be cancelled out. When the electrical
signal of the electrode piece 117 and the electrical signal of the
electrode piece 118 are balanced, the influence on the output
signals of the detection vibrating arms 103a, 103b by the
electrical signals may be eliminated. If the electrode pieces 117,
118 are partially removed, for example, the magnitudes of the
electrical signals may be adjusted. For adjustment of the
electrical signals, it is only necessary that the shapes of the
electrode pieces 117, 118 are controlled, and the formation of cuts
in the first vibrating arms 103a, 103b and the second vibrating
arms 113 may be avoided. The reduction in mechanical strength may
be avoided. The cuts are not formed, and the improvement in
processing accuracy is not necessarily required.
(10) Electronic Apparatus and Others
[0119] FIG. 24 schematically shows a smartphone 201 as a specific
example of an electronic apparatus. The gyro sensor 11 having the
vibrating reeds 15, 15a to 15c is incorporated into the smartphone
201. The gyro sensor 11 may detect the position of the smartphone
201. The so-called motion sensing is performed. The detection
signal of the gyro sensor 11 may be supplied to a micro computer
chip (MPU) 202, for example. The MPU 202 may execute various
processing in response to motion sensing. In addition, this motion
sensing may be used in an electronic apparatus such as a cellular
phone, a portable game machine, a game controller, a car navigation
system, a pointing device, a head mounted display, and a tablet
personal computer. For realization of motion sensing, the gyro
sensor 11 may be incorporated.
[0120] FIG. 25 schematically shows a digital still camera
(hereinafter, referred to as "camera") 203 as another specific
example of an electronic apparatus. The gyro sensor 11 having the
vibrating reeds 15, 15a to 15c is incorporated into the camera 203.
The gyro sensor 11 may detect the position of the camera 203. The
detection signal of the gyro sensor 11 may be supplied to a camera
shake compensation device 204. The camera shake compensation device
204 may shift a specific lens within a lens set 205, for example,
in response to the detection signal of the gyro sensor 11. In this
manner, camera shake is compensated. In addition, camera shake
compensation may be used in a digital video camera. For realization
of camera shake compensation, the gyro sensor 11 may be
incorporated.
[0121] FIG. 26 schematically show an automobile 206 as a specific
example of mobile unit. The gyro sensor 11 having the vibrating
reeds 15, 15a to 15c is incorporated into the automobile 206. The
gyro sensor 11 may detect the position of a vehicle body 207. The
detection signal of the gyro sensor 11 may be supplied to a vehicle
body position controller 208. The vehicle body position controller
208 may control hardness of the suspension and control brakes of
the individual wheels 209 in response to the position of the
vehicle body 207, for example. In addition, this position control
may be used in various mobile units such as a bipedal walking
robot, an aircraft, and a helicopter. For realization of position
control, the gyro sensor 11 may be incorporated.
[0122] Note that the embodiments have been explained in detail as
above, however, a person skilled in the part could understand that
many modifications may be made without substantially departing from
the new matter and effects of the invention. Therefore, those
modified examples may fall within the range of the invention. For
example, in the above described embodiments, the examples of using
quartz as the formation material as the vibrating reed have been
explained, however, another piezoelectric material than quartz may
be used. For example, aluminum nitride (AlN), an oxide substrate of
lithium niobate (LiNbO.sub.3), lithium tantalate (LiTaO.sub.3),
piezoelectric zirconate titanate (PZT), lithium tetraborate
(Li.sub.2B.sub.4O.sub.7), langasite (La.sub.3Ga.sub.5SiO.sub.14),
or the like, a multilayer piezoelectric substrate formed by
stacking a piezoelectric material such as aluminum nitride or
tantalum pentoxide (Ta.sub.2O.sub.5) on a glass substrate, or
piezoelectric ceramics may be used. Further, in the specification
and the drawings, the terms described with the different broader or
synonymous terms may be replaced by the different terms in any part
of the specification and the drawings. Furthermore, the
configurations and movements of the vibrating reeds 15, 15a to 15c,
the gyro sensor 11, the electronic apparatus, the mobile unit are
not limited to those explained in the embodiments, but various
modifications may be made.
[0123] The entire disclosure of Japanese Patent Application No.
2012-102896, filed Apr. 27, 2012 is expressly incorporated by
reference herein.
* * * * *